Operating systems

ShareTask requires an
activation on SharePoint Online, so it is licensed per
organization. One subscription allows upload to an unlimited
number of site colletions within the tenant and activation
on an unlimited number of sites.

Once ShareTask is activated on a site, all users
who have at least Contribute permissions on that site can
reach the lists from their apps.

The ShareTask mobile app is free, so each user can
just download the preferred version.